Typhoon Herb made landfall in northeastern Taiwan on July 31 1996, and was the most damgaing tropical cyclones in the recent history of Taiwan. High-resolution numerical simulations and detailed anlysis were carried out to examine the ability of the model in simulating the track, intensity change, and the detailed mesoscale wind and precipitation distributions associated with Typhoon Herb. Potential vorticity inversion is performed to identify the key synoptic features that control the steering of Herb. Potential vorticity budget is calculated to show the diabatic and topographic effects on the evolution of Herb's intensity. Sensitivity studies with various model resolutions are also carried out to access the impact of horizontal resolution and detailed topography on the mescale wind and rainfall prediction. It is shown that Herb is a case in point to indicate the intimate relation between the rainfall distribution and the Taiwan topography